Regular Or Premium Fuel

[dsvetcov]

On 2015 RX, manual says you can use 87 octane. With price discrepancies between regular and premium, why use anything else? Would like to hear from others on this.

Interesting that the new NX REQUIRES premium as it is turbo charged. One of many reasons I opted for RX.

[pj8708]

On 2015 RX, manual says you can use 87 octane. With price discrepancies between regular and premium, why use anything else? Would like to hear from others on this.

Interesting that the new NX REQUIRES premium as it is turbo charged. One of many reasons I opted for RX.

Hi D,

This question is probably the most frequent one asked by many owners. Prior to 2010 (I'm not 100% on the exact year so flow with me) Lexus car owners were advised to use premium gas. Then in 2010/2011, Lexus made a change for all models to use 87% fuel is so wished. Since then, the owners manuals read that 87% is fine and no problems with warranty issues if the car had only used 87%. I believe that the models with V8's are still required to use premium.

I'm probably like you in that with gas prices what they are, I burn 91% premium. Now, does it go faster? No. Is the mileage any better? No. But I have a lot of pride in my ES. Enough that I give it the best of everything and fortunately I don't have to worry about the dime or more when giving it a drink.

Paul

[13IS250C]

i give my car premium because that is what is recommended. No Paul, I didn't read my manual, it is printed on my gas cap door. I feel like you have to use what your car was engineered to burn.

Our premium in 93 octane.

[JackMR]

I have a 2011 RX-350 and the user manual calls for use of premium gas. I normally use middle-premium and the engine is quite happy. However not all middle-premiums are the same (they are a pump blend of hi-test and regular gas). In rare instances, I experienced a brief hesitation when accelerating from stop or low speed. All I needed is to top the tank with 93 octane and the throttle response returned to normal.

[13IS250C]

Back when I was driving my 95 Z28, gas prices soared and I was feeling the pinch. I filled it up with regular. I hadn't driven 2 miles before it sounded like someone was shuffling a deck of cards under my hood. Thank goodness I worked for an auto parts warehouse so I could go in the back and get a bottle of 104+. I never got stingy with my gas again. I guess it all comes down to the corny cliche....you gotta pay if you want to play.

[1990LS400]

Identical V6 engines have been used in Toyota brand and Lexus brand vehicles for 25+ years. Premium fuel has often been specified for Lexus vehicles and regular fuel for Toyota vehicles. These V6 engines have been rated as being up to four horsepower more powerful when used in Lexus vehicles.

I've compared the part numbers for these V6 engine assemblies used in Toyota and Lexus brand vehicles and the part numbers have been identical. They are the same engines. The same goes for the 1.8 liter 4-cylinder engines used in the Toyota Prius and Lexus CT200h - identical engines with the same part number.

It's good to see that TMC has finally given up on this fairy tale and now specifies the same fuel grade and advertises the same horsepower rating regardless of whether an engine is installed in a "Lexus" or a "Toyota".

If you don't believe me, you can compare the part numbers yourself at http://www.toyodiy.com

[pj8708]

What...??? Not believe you?...Of course I believe you. I never believed that rumor that you did 10 - 12 in a super max prison for smuggling Sugar Plum Fairies. LOL

I am always puzzled by the hodge- podge of different octane fuels around the states. Here our premium is always 91. I know that the oil companies change their formulation during the year for each season. But why the difference in octane?

Happy Holidays,

Paul

[JackMR]

The Lexus and Toyota might be using same engine hardware. But isn't it concievable that the Lexus engine computer is tweaked up for better performance - e.g. spark advance? This may neccesitate use of premium fuel.

[1990LS400]

The Lexus and Toyota might be using same engine hardware. But isn't it concievable that the Lexus engine computer is tweaked up for better performance - e.g. spark advance? This may neccesitate use of premium fuel.

Nope.

The V6 engine in our Camry was rated at 4 HP less than the one in the ES. Regular grade feel was specified for the Camry V6 but our Camry owners manual included a statement that its engine would produce more power if premium grade fuel was used, i.e. the same horsepower as the Lexus ES V6.

A difference that sometimes come in to play is the exhaust system. For example, the current Toyota Avalon and Lexus ES350 are both rated at 268 HP on 87 octane fuel. Both have duel exhaust systems. The same engine in my 2014 Sienna is rated at 266 HP. The difference? The Sienna has a single exhaust system.

There was a similar difference between my 2000 LS400 and the 2000 GS400. The LS400 engine was rated at 290 HP vs. 300 HP for the GS400. The difference? The GS400 had a less restrictive exhaust system.

[Cwdoll]

In our 2012 and 2013 RX we have used regular unleaded. I will tell you that both vehicles still run like new and have never had any issues. If you're going to spend money on your RX, my opinion is there are much better places to spend it on the engine.

[buckmeister2]

On 12/12/2015 at 2:24 PM, 13IS250C said:

i give my car premium because that is what is recommended. No Paul, I didn't read my manual, it is printed on my gas cap door. I feel like you have to use what your car was engineered to burn.

Our premium in 93 octane.

I would imagine the manual and the gas door would be the same...possibly yours is a year that premium is recommended?  The 2015 does not have that recommendation for the 350.